@jmoore, many thanks for that. I suspect you have a bit more research and knowledge behind you than I have, so I'm not going to call you out on any of your points.

We have a well known climate change scientist in Australia who has been ridiculed of late for his earlier dire predictions of drought, in place of which we've had more floods. One thing I will say for him is that he is willing to say "We just don't know enough" and change his position as new data emerges. The climate change skeptics don't.

I just have this feeing deep down that the present commentators (I don't like to say doomsayers or alarmists - I'm talking more about people who present their data saying it's just data and that they can't make predictions from it) are like the canary in the coal mine (an apt analogy :-) and we'd be wise not to ignore them.

You may be right about ocean acidification - on that, I don't have enough information. I am a bit skeptical, simply because the climate scare mongers have been so assertive on so little evidence, so the same sociological phenomenon may be going on with acidification. Think of my skepticism as the application of a bit of Bayesian logic to the a priori probabilities :-)

On climate matters, though, a homeostatic mechanism (if it exists) could counteract a whole lot of CO2 increase. Think of it like negative feedback - probably even non-linear negative feedback.

However atmospheric CO2 concentrations continue rise - so sadly if there are such "homeostatic mechanisms" they are not currently helping us. Furthermore oceans are becoming more acidic which may eventually endanger the existance of all shellfish and corals.

Meanwhile bushfires occur in Australia's south east in October - far earlier in the spring than ever had occured there, ice caps melt, and a hurricane produces an unheard of 235 mph wind (remember from college physics - force grows with the square of the wind speed).

Very scary for our kids and grandkids. And sad that their parents and grandparents shoul be so greedy, selfish and uncaring about the devastating legacy they are leaving.

"It's one thing to scold the government for meddling with individuals' lives and choices. But it's entirely another -- a society with no credible energy policy will end up making everyone wasting his time and resources on stuff that may not have any impact, after all, in actually conserving energy. "

The problem with this view is that billions of people, by necessity, will be outside of that society. India, and even China, face huge obstacles trying to keep their poor from using energy in ways that swamp any policy the developed world can enact. Likewise, even in the developed world, the pain point of policies is hit long before substantial CO2 impact.

The US actually hit its Kyoto goals, even though it isn't a signatory to the treaty. There are two reasons we did so - neither forseeable by energy policy makers:

Frac'ing (really, information processing driven drilling) that has replaced a lot of coal and oii usage with natural gas

The poor state of the economy, which has reduced aggregate energy demand

These should provide a clear lesson to those who wish to use the coercive power of government to make energy policy: you are not as wise as you think - you are likely to do more harm than good.

This lesson will not come as a surprise to those who are influenced by the ideas of Von Mises.

" It demonstates how amazing the current more or less steady state condition of our planet has been for more than thousands of years. Its an amazing balance, the dynamics of which we understand poorly."

That the balance has been maintained is perhaps evidence that the climate system has not-well-understood homeostatic mechanisms (thermostat) that may mitigate the impact of CO2 concentration increase. It doesn't "prove" that they exist, but it is suggestive.

Here are three areas where I think policy actions are taken without regard to quantitative aspects:

(see comment to David Ashton - a lot of detail there) - We accord too much certainty, and rigor to the pronouncements of climatology. We would not do this professionally - engineers are far more rigorous professionally than climatologists. This is not an attack on climatologists - the area they seek to study defies rigorous results (they may apply significant rigor in achieving non-robust results).

CO2 emissions targets are adopted without taking into account their world wide significance (i.e their quantitative benefit). The result is that vast amounts of resource is misdirected. The quantitative aspect is easy to state and hard to solve: how much resource diversion is appropriate, given that even a significant change in developed world energy usage will only make a tiny dent in the CO2 concentration trajectory? The problem is almost never framed that way, and people end up damaging the economy, and feel good about it, because they don't realize the futility of their efforts.

I'm not going to redo the quant math, but the number is surprisingly tiny.

Alternative energy projects tend to be shortsighted. The benefits are often grossly over-estimated. At the same time, they fail to take into account the future - blighting the landscape with bird and bat killing wind farms may be unnecessary damage when future technologies may make those investment a waste. It's the future, I can't predict, but for example, perhaps, thorium nuclear reactors.

I suppose this isn't a quantitative criticism because you can't be quantitative about this - but it's certainly not the way engineers should do things.

We have one very clear example of the folly of #3: corn ethanol. We now know that it has appproximately net zero impact on CO2 emissions. Nevertheless, it has displaced a lot of food production, leading to higher food prices and riots in third world countries (e.g. the tortilla riots in Mexico City). As often happens with government mandates, it has taken on a life of its own (entrenched interests), so that even environmentalists are having great trouble undoing it.

I recently retired, which means I've been around through lots of scares and lots of busted technological predictions. It makes me naturally (and correctly, I assert) waey of the nostrums of the moment.

One problem I have with this debate is that, while engineers must be rigorous in our work, too often we attribute the same rigor to those, such as climate scientists, who are working in fields different from ours. Unfortunately, climatology, whether paleo or prospective (model based) is not at all rigorous when the results are generalize to climate policy.

Also, I doubt we would accept anecdotal information in our fields that we accept in others. For example, the latest big typhoon is probably not the result of "something going on." It is not the strongest tropical cyclone, or even typhoon, in history - Australia was hit by a stronger one a couple of centuries ago. The latest was just another very strong one. As you say about climatology - "the most inexact science." Well, close (psychology is worse). Every bit of the "extreme weather" anecdotes are unsupported by evidence, whether it is Hurrance Katrina, Storm Sandy, this latest typhoon, increasing tornadoes, or whatever. There is no evidence for this currently, and the forecasts are based on weak models (see below).

Once we accord those in other disciplines an inappropriate degree of respect for their rigor, we are then easily fooled by the pronouncements of those in the field with an axe to grind.

I have spent a lot of time on this, as meteorology is a sideline of mine, and I know a bunch of climatologists. The more I look into it, the more I realize how hard the field is, the more I respect those toiling to discern signals from the data and models, and the less I respect those (climatologists) making sweeping pronouncements about extreme weather or forecasted future global mean temperatures.

Here are a few facts:

The climate is not changing unusually fast (if by that we mean global mean temperature). What little we can glean from paleoclimatic data shows that. It also shows that a similar rate of rapid temperature increase happened early in the 1900s, and at a number of other times.

CO2 concentration is increasing more rapidly than at any time we know of. There may have been discrete events like supervolcanoes that were even more abrupt, by they are irrelevant. The CO2 increase is caused by human technology.

The only widely accepted relationship between CO2 concentration and global temperature is logarithmic. A doubling of CO2 produces a ~1.2C temperature rise. All other projections, lower or higher, require feedback (negative or positive) and that feedback is not well understood nor very measurable. Almost every paper published on the topic is based on models (see below). Also, be aware that all serious climate *skeptics* accept the 1.2C/doubling physics - contrary to what you may have read. That 1.2C is based on a one dimensional radiative balance model.

A very few climate scientists are irresponsibly spreading unsupportable alarmist propaganda, and also are deeply invested intellectually, financially and publicly in those arguments. This leads to a lot of FUD in the area, which is unfortunate. Many climate scientists keep their heads down - preferring research to controversy. Others, including some I know, are quietly skeptics but fear to say or publish anything skeptical due to the hysteria about the subject.

Also, the research funding, at least in the US, almost always goes to those who support the climate change hypothesis. The funding bias is so bad that people in unrelated fields tie "climate change" to their research because of it. I found over half a dozen papers tying climate change to prospective effects on surfing, of all things!

There has been no detectable increase in extreme weather. Do *not* be fooled by statements by propagandists. One area where I am active - US tornadoes - provides an ironic example of this. Research severe storms meteorologists of my acquaintance, who are rabid gloom-and-doom "warmists," recently reacted angrily to the assertion that tornadoes were becoming more common and more violent due to global warming - it was rather amusing to see. Tornadoes have are not increasing in intensity or frequency (other than a secular trend due to better detection and reporting). The trend in tornadoes probably has nothing to do with CO2. There is no trend in tropical cyclones (hurricanes, typhoons, cyclones, and whatever you down-under folks call them).

Climate models are at the heart of the debate - especially since the paleoclimatic case for CO2->catastrophic-warming has fallen apart. These models are very complex. They start with the models (GCM's) we use in meteorology for weather forecasting (sometimes even the same Fortran code), modify them to guarantee long term stability (which may or may not damage their accuracy), and then tie them to other models such as biological models and (most importantly) ocean models. BTW... meteorological GCM's are rarely useful for forecasts even 10 days in the future, even with ensemble forecasting.

Contrary to what one might think, climate models are far from being the rigorous physics-based finite element models engineers use so effectively. The GCM's are finite element based, but because the atmosphere is chaotic, and the earth's surface is not smooth, and supercomputer capacity is finite, they cannot make the elements (grid boxes) small enough for physics to be dominant. Hence most of the work on the models, and most of the code, is in "parameterization" - which is an attempt to account for sub-grid-scale processes through other, non-finite-element models. Parameterization can range from a simple adjustment for topography to complex and subtle attempts to forecast chaotic events such as convective storms. Hence the assertion that climate models are physics based is misleading - they are higly dependent on heuristics.

The net of all of this is that these models are highly speculative and have historically done a poor job of forecasting temperature or diagnosing the most critical value in the debate: CO2 forcing sensitivy of global mean temperatures ("climate sensitivity").

The most important factor in radiative balance feedback is clouds. They can provide either positive or negative feedback. Models are not good at forecasting cloud feedback, to the point that not even the sign (postive or negative) of cloud feedback is well understood.

Probably the most critical component of the climate system is the oceans, because they have tens of thousands of times the heat capacity of the atmosphere. Ocean feedback is not even close to being understood - partly because the ocean has multi-decadal cycles for which we don't have good long-term measurements. Also, there are chaotic elements in ocean heat transport. Note that ocean heat transport is a bit weird - unlike the atmosphere, we heat the ocean from the top, which prevents convection from vertically mixing the heat, and the heat conductivity of the ocean isn't nearly enough to move the amount of heat involved (it's something like .25W/m^2).

The global mean surface temperature has not increased in 17 years. No climate models predicted this. Also, the surface temps are no higher now than they were 1000 years ago (some will disagree). This doesn't mean that CO2 emissions aren't causing warming, but it should give pause to those who claim they understand warming or the impact of CO2.

I hope this rather long discussion serves to inform about the dangers of relying on climate predictions. The fact is: we don't know - certainly not as well as any engineer would require before making a professional recommendation.

As far as policy prescriptions go... first, we need to recognize that sane policy prescriptions (if such a thing is possibly) must necessarily be unscientific - they have to take the output of weak scientific processes and include non-scientific variables such as economic and social effects.

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I disagree with the "we must do something" approach on logical principles.

But, I do think there are things we should, and shouldn't do:

We should continue research in climatology. However, we should cut back on the funding going to climate modeling. The US has spent $150bn on this, and it's too much. More money won't yield better science - in fact, a fair amount less money will yield science that is just fine.

We should continue to develop alternative energy, but not by forcing today's uneconomic energy nostrums (such as photovoltaics) down everyone's throat, but rather being future focused and recognizing that future technological and social conditions cannot be readily predicted. In other words, other than research and spot applications where the benefit is clear, we should wait rather than make large energy changes. Of course, there are plenty of arguments beyond climate for improving fuel economies.

We should reseach climate adaptation. If CO2 causes climate change (and at some level, it must), it is more likely that we will have to adapt to it rather than being able to prevent the emissions. Hence we need to look at technological mitigation (ways to decrease the warming), and at technological adaptation (living with a warmed earth).

Finally, to address your pessimism. Yes, I agree (oh, and I'm a bit older than even you :-). Beyond that, barring unforseen technological innovations, I think it is inhumane to deny the people of developing nations the benefits of increased energy intensity.

But on the positive side, the climate impact of CO2 probably isn't as bad as you think. As to the other scare, ocean acidification, I have no idea.

"I want to ask you, readers, where you think our current policies have gone wrong or are missing the point (when it comes to energy conservation), and what you hope to propose instead."

Seems to me that a continued emphasis on improving efficiency of all manner of machinery is a good thing, but I also think it's not going to be the major part of the solution. Rich people will buy that efficient car or refrigerator, and feel all proud of themselves. But the increased demand for energy in the next decades is from people who are really really poor, and have a tiny carbon footprint now. So figure it out, tree huggers. We need more than self-congratulations.

I think the politicians should have placed exactly the same fuel economy mandates on all privately owned vehicles. None of this waffling about obscene SUVs getting a more lenient number. That would curb some of the hypocracy we see daily, even if it doesn't solve the (potential, or even likely) CO2 problem.

But most of all, it really bothers me to see that weather globe on France 24 news, where it shows green and tan expanses of our gorgeous planet. We need to work to get more of that land mass looking green.

"We already have that. The build up of CO2 is known to be from fossil sources because plants absorb less C13 than C12 given their ratio in the atmosphere. Thus, fossil fuels also have a lower C13/C12 ratio than the atmosphere, and when burned, should cause the atmospheric ratio to drop in turn."

Partial explanations seem designed for dramatic effect.

You're saying that the C13/C12 ratio in the atmosphere is dropping, slightly, which indicates that man-made CO2 is the largest contributor of **rising** CO2 levels. What the unwashed interpret, from the now prevalent partial information, is that humans cause MOST of the CO2 output. Good recipe for global hysteria. "Most of the increase" is not the same as "most of the quantity." Like my previous example, if you go from adding one glass of water to the ocean, to two glasses of water, or even 10, you still wouldn't expect a big change in sea level. And yet, you could make that sound dramatic. He's adding 10 times more water to the ocean than he did yesterday!

So, today humans are dumping just about 3.1 percent of the total daily CO2 into the ecosystem. You can verify this.

Although that C13/C12 ratio explanation, to prove the additional CO2 levels are man-made, isn't without its detractors, it doesn't contradict my point. The daily human contribution is very very small compared with the daily total from natural causes, and reforestation in large scale would regulate that increased CO2 volume. Reforestation wouldn't care who made that CO2. The trees would grab it regardless, and in fact, would preferentially extract the C12 isotope. Since humans caused most of the deforestation, that seems like a slam-dunk first measure to me! Every tree you knock down has to balanced by a new tree planted. Or more than one.

We know that there's a big pent-up demand for luxuries in the two by far most populated countries on the planet: India and China. Roughly 1 of every 3 people on earth is from those two countries. So obviously, demand for fuels is going to grow too. It makes a whole lot more sense to see to it that the extra CO2 emissions will regulate themselves, I mean through photosynthesis, than it does to pretend we're going to stop people from buying the same luxuries we have, or that we can sequester and bury all of the human-generated CO2, or even that if the developed countries drop their CO2 emissions by some small amount, that would solve the bigger problem.